the advent of mines, torpedoes, submarines and long-range coastal artillery. By 1912, Airships and aircraft could uncover the position of the bigger ships off shore and direct submarines and destroyers towards them. During the Russo-Japanese War (1904–1905), the Japanese fleet conducting the last close blockade, of Port Arthur, had suffered many losses from mines. The Navy policy for blockade evolved, in 1908 the commander of the Channel Fleet ordered that the big ships would move to positions beyond the range at which German destroyers could not reach if sailing at nightfall with orders to return the next morning, reckoned to be . British ships in the Heligoland Bight should try to cut off German ships sailing from the Elbe or Jade or report the sailing of the High Seas Fleet (). The Admiralty had a change of heart in 1911 but by 1912 th war orders stipulated that a close blockade was superseded by an observational blockade formed by cruisers and destroyers ranged from the Norwegian south-west coast, to half-way between Germany and England, level with Newcastle, then south to Texel with the Battle Fleet cruising to the west of the line. Plans from 1905 to capture a German North Sea island as a forward base were also abandoned after the Germans fortified Heligoland and the Frisian Islands and the Grand Fleet war plans of June 1914 scrapped the observational blockade for the Grand Fleet to be based in Scotland except for the Channel Fleet which would remain on the south coast. The bases of the Grand Fleet were to block the northern exists of the North Sea and the Channel Fleet to seal the channel. The northerly line would stretch from the Scottish coast and northern islands to Norway, with the Grand Fleet based at Scapa Flow in Orkney with un-armoured cruisers (later named the Northern Patrol) patrolling a line from the Shetlands to the Norwegian coast. The German navy was ignorant of the new policy and expected to find plenty of opportunities to whittle away the numerical superiority of the British. North Sea exits In a naval war with Germany, Britain had the great geographical advantage of obstructing German access to the Atlantic Ocean. Should German ships seek to use the southern exit of the North Sea, they would have to pass through the Strait of Dover and along the English Channel, which for was no more than